Conclusion
These findings identify a novel role of PrLZ in autophagy manipulation and provide new insight into docetaxel chemoresistance in PCa, suggesting a new strategy for treating mCRPC by targeting this newly identified signaling pathway.
Methods
Human PCa PC3, LNCaP and C4-2 cell lines were used as the model system in vitro and PCa xenografts and PrLZ-knockout mice were used as the model system in vivo. Docetaxel-induced cell death and apoptosis in PCa were determined by MTT and flow cytometry assay. The role of PrLZ on the regulation of autophagy and liver kinase B1/AMP-activated protein kinase (LKB1/AMPK) signaling pathway was analyzed using immunoblotting, immunoprecipitation, siRNA silencing and plasmid overexpression.
Results
PrLZ increased docetaxel-mediated drug resistance both in vitro and in vivo. Mechanistic dissection revealed that PrLZ interacted with LKB1 and further inhibited the activation of LKB1/AMPK signals, which negatively contributed to the induction of autophagy. Moreover, PrLZ/LKB1-mediated autophagy conferred resistance to docetaxel-induced cell death and apoptosis both in vitro and in vivo.